Broken build, vue-cli removed build command in 2.9

Hi,

I'm starting learning Apollo and it's integration in VueJS, thanks for your work !
There's a small problem to build the project : the recent vue-cli 2.9 version removed the build command and advice to use Poi (https://github.com/egoist/poi)

A temporary fix is to install vue-cli 2.8.2 in project dev dependencies :
````
npm install -D vue-cli@2.8
````

And use project vue-cli in package.json scripts :
````
"scripts": {
"dev": "./node_modules/.bin/vue build src/index.js --config config.js",
"build": "./node_modules/.bin/vue build src/index.js --config config.js --prod"
}
````